Lawn edger



April 14, 1953 G. w. woloLwlNE LAwN EDGER Filed Nov. 18,"194'7 1 W w e A TTORNEYS.

Patemed Apr; 14,' 1953 UNITED STATES TENT OFFICE LAWN EDGER George W. Woolwine, Selma, Calif. Application November 18, 1947, Serial No. 786,558

3 Claims. 1

The present invention relates to lawn trimming tools and more particularly to a lawn edger employing a pair of circular cutting members frictionally rotated in substantially unitary relation in rolling earth traversing movement to achieve a positive cutting action therebetween.

It is well known that a great many lawn edgers employing a circular disc have been produced' and are known to the prior art. It has, however, been found that none of these prior known edgers have worked satisfactorily because they usually result in pushing the grass down into a crack between the sod and the cement rather than trimming evenly and positively.

An object of my invention is to provide a lawn edger or trimmer which has a positive cutting action and does not depend on a backing of the concrete or sod in order to cut or trim the grass.

It is a further object of my invention to produce a lawn trimmer which requires relatively little manual force in order to trim the grass and edge the lawn.

Prior known lawn trimmers which depend on a positive cutting action for their trimming ability have usually taken the form of a rotating cutter adapted to roll with its Cutting edge against the concrete, thereby cutting the grass and sod. It will be clear to those skilled in the art that such a device is unsatisfactory in that the cutting edge has a Very short life when rolled against such obstructions as concrete. It is among the objects of my invention to produce a rotating cutter-type lawn trimmer wherein the cutting edge of a rotating cutter rides against a 'relatively smooth metal surface thereby increasing the length of life of the cutting edge.

It'is a further object of my invention to produce a rotating cutter-type lawn edger wherein the Cutting edge rotates against a hacking with a substantially Constant tension wherein said tension is obtained by a resilient member and not by the force of manual labor applied to the cutter.

So far as is known to me, no lawn edgers have been produced wherein the depth of cut or trim can'be regulated at will. It is also among the objects of my invention to produce a lawn trimmer having vadjustable means thereon so that the trimming blade can be vertically adjusted with respect to the level of the sidewalk or other obstructions along which the edger is motivated.

Other and furt-her objects and advantages of my lawn edger will become apparent from the drawings and the specifications relative thereto.

' In the drawings:

Figure l is a side elevation of a lawn trimmer embodying the principles of my invention.

Figure 2. is a fragmentary sectional view taken on line 2-2 of Figure 1.

Figure 3 is a sectional view taken on line 3-3 of Figure 2.

In the drawings, I have illustrated what I consider to be a preferred embodiment from the standpoint of both operation and manufacture. It is to be understocd that a great many modifications, which will become apparent from a more detailed description, can be made within the scope of my invention. It is further to be understood that the embodiment herein illustrated and described is by way of illustration and not limitation.

My invention comprises essentially a handle lt having a vertically rotating cutter disc ll and an obliquely rotating cutter blade |2 adapted to rotate against a side of the vertically rotating disc li, thereby providing a positive cutting action.

The handle IO is provided with a shank |5 on the lower end thereof, which is illustrated herein as a rectangular bar. It will be, of course, understood that any desired Shape, such as a rod or hollow tube, can be employed, the purpose merely being to provide a means for connecting the rotating cutters to the handle. The shank 15 is formed with a transverse bore IG through which an axle l'l is disposed.

The axle Ii has a reduced end portion l8 which deflnes a shoulder 19. The outer end of the reduced end portion l is threaded and adapted to receive a nut 2B. The purpose of such structure is readily ap'parent in that the nut binds against the shank |5 and holds the axle l'i rigidiy in position. The outer end of the axle ll is formed with an enlarged head 2i, the purpose of which will be apparent from a further description of the function and structure.V

The Vertical disc Il is circular in form and is provided with a friction-drive hub 25 which is concentric with the disc il, axially extended from a side thereof and secured thereto by any suitable means, such as welding as at 26. The friction hub 25 is formed with a centrally concaved portion 21 and a centrally located aperture 2a. The disc H is also formed with a centrally located aperture 29 which is concentric With the aperture 23. Aperture 29 is herein irllustrated as of equal diameter to the apertur'e'vZB, but such equality is not essential, the purposeof these apertures being to receive a bearing member 30 having a longitudinal bore 3| rotatably and slidably mounted on the axle The bearing member 30 is securely fastened to the disc by any suitable means, such as welding, as at 32.

It Will be readily understood that the purpose of the concave section 21 is to provide a recess so the head 2| will be fiush with the hub 25. This is, however, a matter of choice and should not be considered a limitation on my invention.

A washer 35 is disposed over the shaft |1 and is adapted to act as a bearing surface between the bearing member 30 and a compression spring 36. The compression spring 36 is disposed in compression between the head 2| and the bearing washer 35. The purpose of the compression spring 36 will become readily apparent.

The rotating cutter blade 2 is preferably formed in a concavo-convex shape and has .a peripheral cutting edge 40 adapted to ride 'against the surface of the Vertical disc I. The concavoconvex blade |2 is rotatably mounted on a shaft 4| and has its axis of rotation in substantially fa common plane with the axis of rotation of the Vertical disc but intersecting said axis obliquely.

The shaft 4| is formed with an offset leg 42 having a reduced end portion 43 and threaded 'end 44. A bearing member 45 is disposed in the center of the blade |2 and secured thereto by any suitable means, such as a press fit or Welding 46. The bearing member 45 is adapted to ride in a thrust relationship against a shoulder 4,? defined by the offset leg 42 and the reduced end section `43. A washer 48 is disposed over the end 44 of 'the shaft and securely held in position by a lock nut 49. If desired, a thrust bearing may be interposed between the bearing member 45 and the shoulder 41.

A socket member 55 is securely mounted on the shank by means of set screws 56, and formed with a bore 51 parallel with the shank |5. The shaft 4| is disposed through the bore 51 and is adjustably held in position by means of a thumb screw 58. The shaft 4| can assume a great variety of shapes. It is herein illustrated as a round rod having a fiat side 60 (see Figure 3). The purpose of the flat side is to prevent rotation of the shaft 4|. It would be apparent that square bars could be used with equal efiiciency. However, it is believed that a round rod having a flat side is the preferred form because from a manufacturing standpoint, it is easier to drill the bore 51 round than it is to broach a square hole through the block 55.

The purpose of the spring 36 is to provide a constant tensional engagement between the vertical cutting disc and the peripheral cutting edge of the concavo-convex blade 2. It is readily apparent that this same function can be obtained by other means such as, for example, by placing the spring 36Vbetween the washer 48 and the blade |2, which would urge the blade |2 inwardly against the disc or as another example, by placing a coil spring in tension between the| shaft 4| and the block 55 which would also urgethe blade |2 against the disc because of a 'rotational force acting on the shaft 4|. i i I have herein illustrated the blade |2 as a concavo-convex disc. Such form is preferred because Vit is more desirable to have the cutting edge 40 ride at right angles to the surface of the disc which can be accomplished with a greater cutting angle on the cutting edge 40 when the disc is substantiallyconcavo-convex,

It is desirable to be able to adjust the vertical position of the cutting blade |2 with respect to i the cutting disc so that any desired depth of cut in the trimming operation may be made. In order to achieve this purpose, I have herein shown a means for adjusting the position of the rod 4| vertically within the block 55. It will, of course, be apparent that the same function can be obtained by making the block 55 adjustable with respect to the shank,, |5orhy subfstituting in place of the shaft 4|` .a telescoping mount adapted to support the oblique section 42.

.It will readily be understood that the important features of my invention reside in a lawn edger having a Vertical cutting disc resiliently engaging in cutting relationship an oblique cutting blade whose point of engagement therewith is radially adjustable relative to the disc. Further it will be readily apparent that the disc and the drive hub 25 may be rotated in unitary relation by any suitable ,driving meansysuchnas a small gasoline engine, orv the l ike,in= driving connection therewith. Poweredflrivingp he cutter blade and drive hub has been found particularly advantageous -in trimming the edgesiof plots of grass adjacent side walks, curbingsbheadstone markers in Cemeteries, and other -bounding' means, where the grass is found to beparticularly tenacious inV character and/o1- the earthjfir 'ly compacted adjacent said boundingmea While I have herein shown and ,descri-be my invention in what I have. conceived to be the cst practical and preferred embodimnt. itj-r nized that departures-=may be made the7 within the scope of myinvention, which to be limited to the detailsv disclosed herein, is to be accorded the full scope of the claims to embrace any and all equivalent devices Having described my invention, 'wha'tQI la as new and desire to secure by Lettersatentis: 1. A lawn edger comprising Va handlehavinga lower end portion, an axle mounted transversely on the lower end portion of the handle, a circular disc having substantially flat sides rotatably mounted concentrically .on the axle in substa tially parallel relation to the handle and-forex l slidable movement toward and from the hand a cylindrical hub integral with the disc and vconcentrically and axially extended from a lside thereof away from the handle, a shaftlvmounted on the handle in substantially parallel relation to the handle and opposite to the handle from the disc and for adjustable positioning flongitudinally of the handle, said shaft havingan angled end portion directed outwardlyfrom lthe handle and away from the disc, a circular concaVo-convex blade having a peripheral ,cutting edge rotatably mounted concentrically V'on said end portion of the shaft with its concave vside toward the disc and its cutting edge in engagement with a side of the flat disc at a position spaced radially inwardly fromthe peripheryjof the disc, and resilient means mounted on theaxle urging the flat disc axially against the cutting edge of the concavo-convex blade. i

2. A lawn edger comprising an elongatedhandle, an axle mounted `transversely on the handle, a substantially fiat circular disc rotatably mounted concentrically on the axle, said axle having an enlarged head in spaced relation `to the handle whereby axial movement-of the disc on theaxle is accommodated betweenthe handle and the head, a shaft mounted on the handle having a journal portion: adkjaclentto' the axle and in coplanar relationtherewithhsaid journal portion being extended outwardly from the handle and away from the disc in a plane common to the axle, a concavo-convex blade having a peripheral cutting edge rotatably mounted concentrically on the journal portion of the shaft with the concave side of the blade disposed toward the disc and the peripheral cutting edge of the blade in rolling engagement with a fiat side of the disc at a position spaced radially inwardly from the periphery of the disc, and a compression spring mounted between the disc and the head of the axle Whereby the disc is urged axially into engagement with the cutting edge of the blade.

3. A lawn edger comprising an elongated handle, an axle mounted transversely on the handle having an enlarged head in spaced relation to the handle, a substantially flat crcular disc rotatably mounted concentrically on the axle between the handle and the head of the axle, a block mounted on the handle having a bore formed therein in substantially parallel relation to the handle, a shaft having a longitudinal fiat mounted in the bore of the block for adjustable positioning longitudinally thereof, screw-threaded means mounted in the block engageable with the flat of the shaft to lock the shaft in longitudinally adjustable position in the bore and to preclude rotation of the shaft in the bore, said shaft having an angularly related journal portion adjacent to the axle extended outwardly from the handle and away from the disc in a plane common to the axle, a concavo-convex blade having a peripheral cutting edge rotatably mounted concentrically on the journal portion of the shaft with the concave side of the blade disposed toward the disc, and With the peripheral cutting edge in rolling engagement with the adjacent side of the disc at a point spaced radially inwardly from the periphery of the disc, a stop mounted on the extended end of the journal portion of the shaft limiting axial movement of the blade on said journal portion away from the disc, and a compression spring mounted between the head of the axle and the disc urging the disc into continuous engagement with the cutting edge of the blade.

GEORGE W. WOOLWINE.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 331,804 Mason Dec. 8, 1885 1,127,764 Huck Feb. 9, 1915 1,916,'725 Harbour et al. July 4, 1933 1,970,827 Van Kesteren Aug. 21, 1934 2,212,057 Waller Aug. 20, 1940 

